Trailer dolly



Aug. 22, 1950 L. c. HAGG 2,519,564

TRAILER DOLLY Filed Oct. 20, 1947 s Sheet-Sheet 1 HTTOENEV c. HAGG TRAILER DOLLY Aug. 22, 1950 3 Sheets-Sheet 3 Filed Oct. 20, 1947 INVENTOR.

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nrroe/vey "This invention relates two axles do not balance the trailer.

Patented Aug. 22, 1950 UNITEDfiSTATES PATENT OFFICE F 2519,5 41 j v TRAILER DOLLY Leo Charles Hagg, Kenewick, Wash. Application October 20, 1947, Serial No. 780,919

V 'to a mechanical dolly and particularly to a dolly for use between a towing automobile and a trailer.

Trailers are generally connected to the towing automobile or car by means of a tongue which "'usually-being'connected to the frame on the aft part of the-car. Most'trailers are mounted upon a 'single axle with wheels and those that employ A considerable proportion of the weight of the trailer must be carried by the towing car. The lack of 'balance exerts considerable stress on the frame of the car and on' the structure of the trailer, which resultsin frequent repairs, and aside from the frequentrepairs, considerable annoyance'is experienced by the jerk of the trailer when it is unbalanced relative to the car. Often it is necessary to supply the towing car with overload springs in order to absorb the stresses of the trailer, particularly when heavy trailers are required. It is highly desirable, when towing a trailer, that the floor or body of the trailer be maintained in a horizontal plane. It is necessary, in order-toaccomplish this objective, to be able to raise or lower' the tongue of the trailer.

. The present invention not only provides a dolly beneath the tongue of the trailer (between the towing car and the trailer) whereby the downward load of the trailer is absorbed (in part, at least) whereby the automobile used for towing is relieved of'the excessive load, but in addition,

I this invention providesmeans whereby the vertical' position "of the tongue 'may be selectively established at any vdesiredlevel, thereby permitting the tow car to pull the trailer with the latter atthe most eflicient level or balance point for effective, smooth towing.

Also, considerable difliculty is experienced when backing a trailer hitched onto a towing car. Naturally, when the trailer is connected directly to a hitch fixed to the frame of a towing car,

the-trailer hasa tendency to go in the opposite direction than the towing car when backing.

Still furthenwhen the towing car is encumbered with considerable weight of the trailer, there is of the trailer and provide means whereby smooth and straight pull isobtained therebetween.

Another object is to provide a dolly for use with trailers whereinthe dolly is connected to 2Claims. (c1.2s-se.4)

the towing car in such a manner asto operate independently of the main hitch between the towingcar and the trailer.

A further object is to provide a dolly for use with trailers which will obviate props or jacks when parking a trailer independently of the towing car.

A still further object is to provide a dolly having the above characteristics that may be readily applied to the construction of the conventional connection heretofore provided between the trailer and the towingcar.

A still further object is to provide a dolly of a type'that may be readily adjusted for taking any desired amount of the weight of a trailer off of a towing car and be readily adjustable for any load condition that may arise.

Other objects will be made apparent throughout the further description of the invention when taken in connection with the accompanying drawings, some of which will reside in the simplicity,'ruggedness, agility and synchronism of the dolly in connection with the inherent operation of the turning movements of both the towing car and the trailer. It is to be understood that the drawings are illustrative of exemplary forms which will enable one skilled in the art to produce a structure embodying the invention.

While various modifications may be illustrated, the embodiments here shown are merely some of the preferred structures.

. In the drawings:

Fig. l is a top plan view of a device embodying the invention shown connected between fragtrating a different means for connecting the axle of the dolly with a cross bar carried by the towing car.

'7 is a View similar to Fig. 2 illustrating I another-embodiment of the invention.

" that will relieve the towing car of excessive weight Fig. 8 is a sectional view taken along theline VIII-'-VIII of Fig.7. a e

Referring to the drawings, Ill indicates a towing vehicle, such as an automobile or a truck, having fixed to the aft end of the frame a hitch ll arranged to be connected with a tongue, repre- 's'ented in its entirety by-IE, of a house trailer or is provided with a riser jack or adjustable" foot for the purpose of supporting the tongueJZ in a substantially horizontal position whenthe trailer is disengaged from the towcariand parked. The present invention mayebeireadilysadapted for use with the connection above described and is arranged to operate independently of.the4zon bolts 36, the latter being threaded into vertical openings in the axle l8. The bolts 36 may have bifurcated upper end portions for receiving the rear ends of rods 39 of the draw bar 33, the rods of the bolts 36-=by means of pinsiiBfvvhereby a turning movement in a vertical plane is peri mitted.

.It,has been found necessary that a certain 10 resiliency be provided between the cross bar 34 v:andE-tl-ie axle. l8. This is effected by the oppo- .sitely disposed springs carried by the rods 39 and 40, each acting separately to efiect the required pull :between the axle l8 and the cross bar 34.

ventional connection between the trailer and the 15 It can be seen from the drawings that the draw ilmvirgg 34 In .the formashown, :theretis aprowvidedeana-axlez m-Lmountedgen suitableaneumatic wheels 32, preferably temploying .EIimken -:bearaingsiorrot-suchrtyneewhiehewill permittlong usage Without lubrication. .iInsthe -embodiment shown "tin Figs; l-atO-fl; inclusive,-.there is: mounted: omeach side of the axle IS a pair of leaf -:springs m9, nthei ends: n1 which: are pivoted --to =shack1es:29,\ the eShiLGklQS, ;-21fi-,'being'.maunted on suitablelbracketsd I carried? by the {axle its and adjacent =t-he tcorrecspondingiwheelssiii.

Centrallyof ttheisprings tthere lis nrmzided tnlomiting platet-22, -t1 1e latter being-fixed z-tOR the spririssllfi hyirneans ofaUeshapedclampsasshown tat 2-4. Carried;byethezmounting plate zzxis-latsup- .ihaving agstubxshafmextending:unwariilygthetend of which is providedrwithza secket iil star receiving the lower end of a :conventional rising i ack 16-1 in order :that the present device may be independently drawnbythe drawing-canitherezis V ;pr0v-ided ;a pair of draw rLOdS or slinktconnections, each of which may consistxofia drawbazr, arepresented in its :eentirety :33. Each of "the draw bars 33 consists of a centrallyilccated cylinidr-icaL-member :30 havingiclcsedends. lIhezends ,55

of the cylindrical member are provided with taxially alignedopeningsfcrreceivingconnecting .tmdsriid and-A18. Theadjacentendsof rods :38 and 459 :are rflanged ato fcrmseats :ior a pair of "coil springs disposed around the rods 39 and ihand ,wiirhinethercylindrical member-r30. The ends of the vmember 3t provide oppesingrseatsiordahacowqperating tends of the springs. {The rods and 58 are free to slide within the cylinder 33 against vthestension of the springs.

The drawibars 93.3 are -utilized to monnect the axle ifi-rofiehe trailerwitha.cross bar 34 carried by the towing car. The cross bandits-preferably .pcsitioned para1lel to the rear axlevofithe :towing car andimay be attachedto theconventionalcar? hitch .1! i, such as by welding or by the :use of .bolts andethe like. Thereisfof soun -ascertain amount of .vertical movement of the .draw .bars id3ewith respect vtothe axle -l8,vand thedrawibars Within ithe W35 :In other words, 3113 is desired that :tne .40

bars fid-lmay beeadj ustedi-by .means lcfnthe thread- -.ed econnections .39 on rods '40. it is aimportant that these drawlbars besequally-adjustedeso that :the axle t8 (of the -dolly twill vrun 'in parallel .20 saligmnentwith therear axle of \the drawing: car.

Marious rmeans,-. such as illustrated xatA 5,? may be .;provided for connecting (the qforward end of ithe .rod 419 =-.t0 the across rbar e34. \Such emeans Jmust ;;pro-vide [for 5 pivotal connection between i the cross .-bar $4 ear-Id the adjacent ends; of the connecting l redeem. iID. order :ato provideforturnablevmovecment ibothein a horizontal and zvertical-plane, the means-745 mayincludea swivel dointA Lhaving ea verticallysextending stud- 42;.projectingupward- ,iiyahrou'gh=theecross bar-.-34. The swivel joints ZAI are *held .in assembled (relation with ithe rcrcss ibarcdibyimeans of internally threadedz-mem-bers :43, havingianzoperating head44. -'Ihe-*head'44 may-be of any design whereby .an-roperatortmay gr-as-p -.-the.-asamer for :readily attaching or detachtingKEhBQQIIBSBDtZdGViCG -.to rthe: crossibar' 34.

Fig. 5 1illustrates another manneriimwhichethe esprings I 9 of itherdolly Jnay :be connected to the iriserjri-acmsl. =;In:this form-the:supportingihead e23 imay be separated :from :the supporting :,.plate 22 :andprovide'd with aa zcentral; circular openiing, t-ltogether with vertically aligned openings positioned z-ax-ially 0f :the .cylindrical :recess. 525. Hilde -:ball .126 :is there afiixed :to :thexasupporting plate 212 and 'the :uppert-opening 29 -is-:enrploy.ed siaszarsocket for:reeeiving-stheilower:endlefctherriser iack ifll. Thempening n28?- maytbeaelonga'ted in carrier ato rpermit :relati ve smovement of ithe axle 1:8 in .aa stransverse aplanei .sln 'cthis :construction -thess.upportingzheada2":may:consist iifetwoiparts halted together as :clearly:showmby;Eig.i5'..

Rig. 6 illustrates. another dorm 'by means :of mhichathe-rconnecting mcids it zmay *heraffixed zto the axle [8. In the formishowiniioy rl 'ig. sea'ch iofzthe -vertiedl house-316's carried 'cbyithe shatt l8 .iisiprovidediwitiv a es'hapeilzmemherdiaiiingilegs Q6 452,. :Theifree'aends iof: zthe: legs *Afirand 1&6 eare-ccarriedqbyxrtheflupperzeand zlower end, ,rresnecti zelygoiatheibolt 36L :5 The dlosedrends mi ctherzlegsrsliifi and 455.501 the EU shaped member ,tmayrbeipivotedwtogether andwthevfree end or ithe zrodqdfi pivoted Joy a sin'gle,-v.connecti'on;as shown flat 3B3 fiIn thisaform,wtheiinnerrendeof zthe rred 33 may the -,permitted -to iturnrin ta yentical gplane at Qthe flaoint-fafi awhile ,zthe ilegsguifi randgfif :may turn in a horizontal plane-cabout ithewboltt'fiii.

aknother termini .themresentxdevice as :illus- ,trated :'in :7 rand-A3 pmay meside ;in. -.provi'ding t-a supporting .plate 4-? ion ither axle 418. I The sup- -ponting;plate-M ma y he rigidlyfixed=thereto by welding rand having-spaced thereon -.tWQ epair 01' vertical members -49 disposed 10H pppositessides of axle-i3 cfind arranged ;to .support -;a horizontal member at. ThQ-illlfifilhfif 5i mayzrhave disposed wm e d W e a 8 y means-9i as g em e ese ineesfiz tmiougn which the. wertieal members 49 extend and are slidably connected therewith. Springs 53 may be disposed about member 49 and interposed between the supporting members 41 and 5! for absorbing the usual shock that occurs in normal operation.

In this embodiment, there is provided vertical threaded members 55, preferably disposed adjacent the ends of the supporting member 5| and arranged to adjustably support a supporting plate 56, suitable threaded means 51 being provided for adjusting the height of the supporting plate 56. In this latter embodiment the dolly may be positioned directly under the hitch ball H. In fact, in this embodiment it is desired that the hitch ball I! be carried by the car hitch directly above the supporting plate 56 to which the socket l6 of the tongue I2 is connected.

In the embodiments illustrated in Figs. 1 to 6 inclusive, it is important that the draw bars 33 be properly aligned and. adjusted by the means 39 in order that the cross bar 34 will be normally parallel to the axle [8 of the dolly. This will effect proper turning of the dolly relative to the rear axle of the towing car, whereb similar movement of the trailer is obtained.

It has been found that a dolly constructed of light weight, strong material may be utilized in connection with trailers of various lengths and weights. The present construction does not only reduce the shock due to change of speed but it operates to prevent side swaying of the trailer and, consequently, saves wear and tear on the tires.

It will be obvious from the above description that the present device may be readily adapted to the conventional hitch between any towing vehicle and a vehicle to be towed. Many of the heavier types of trailers exert considerable pressure on the aft end of the towing vehicle and because of the weight on the aft end of the towing car it is oftentimes necessary to provide additional springs to compensate for this additional weight. By the use of the present device, the addition of extra springs is obviated. Aside from the smooth, straight pull produced between the pulling car and the trailer, it might be also well to mention that the present device obviates the use of props or jacks when parking a trailer. It will also be noted that the present dolly operates independently of the car hitch and that the dolly may be raised and lowered to provide any desired weight on the aft end of a towing vehicle.

The present device is readily adapted to most of the conventional trailer and car hitches without any alteration to the mechanism.

Accordingly. there is provided a mechanical dollv for use in absorbing the stresses between a towing car and a trailer which will prevent the undesirable jerks and stresses usually experienced and provide smooth, straight pull even on irregular roads or terrains. The present device does not only r duce the shocks between the towing car and the vehicle being towed but prolongs the mechanical life of both vehicles and provides an intermediate assembly which aids in the maneuvering of a vehicle being towed, since the drawbar carried by the drawing car is arranged to be substantially parallel to the axle of the dolly and independently connected to the drawing car without aid from the conventional connection of the car hitch and the tongue of a Vehicle to be drawn.

While I have illustrated and described the present invention in connection with a drawing car and a car to be drawn, it will be obvious to those skilled in the art that the present dolly may be employed in numerous mechanical devices where there is relative movement between two moving objects. Other changes, additions and omissions may be made in the exemplary for-ms sh'ciwn without departing from the spirit and scope of the invention.

I claim:

1. A trailer dolly for house trailers provided with a tongue extending forwardly beyond the trailer and a hitch carried thereby and attachable to a draw bar of a drawing vehicle, comprising: a wheel axle provided with a pair of spaced wheels adapted to extend beneath the tongue; a pair of parallel leaf springs, one on each side of the axle, the ends of each of said springs being pivotally connected to the wheel axle below the plane of the axle and the midpoints of said springs being above the plane of the axle; a mounting plate connecting the leaf springs midway of the wheels and above the axle; a vertically adjustable riser jack carried by the tongue adjacent the hitch; and a rotatable connection between said jack and mounting plate, whereby height of the tongue and the load carried by the dolly may be varied :by adjustment of the riser jack.

2. A trailer dolly for house trailers provided with a tongue extending forwardly beyond the trailer and a hitch carried thereby and attachable to a draw bar of a drawing vehicle, comprising: a wheel axle provided with a pair of spaced wheels adapted to extend beneath the tongue; a pair of parallel leaf springs, one on each side of the axle, the ends of each of said springs being pivotally connected to the wheel axle below the plane of the axle and the midpoints of said springs being above the plane of the axle; a mounting plate connecting the leaf springs midway of the wheels and above the axle; a vertically adjustable riser jack carried by the tongue adjacent the hitch; a rotatable connection between said jack and mounting plate, whereby height of the tongue and the load carried by the dolly may be varied by adjustment of the riser jack; and a pair of spring-biased, parallel, link connectors pivotally attached to the axle and extending at right angles thereto, the forward end of each of said spring-biased link connectors being provided with means for adjusting the length thereof and means for connecting the same to a drawing vehicle, whereby said dolly may be drawn independently of the house trailer.

LEO CHARLES HAGG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 355,341 Saladee Jan. 4, 1887 1,325,162 McGriff Dec. 16, 1919 1,490,093 Coplantz Apr. 15, 1924 1,773,313 Lundelius Aug. 19, 1930 2,189,170 Gaussion Feb. 6, 1940 2,302,246 Nelson Nov. 17, 1942 2,331,006 Suttles Oct. 5, 1943 2,376,001 Nogle May 15, 1945 2,378,297 Hetzler June 12, 1945 2,410,241 Schramm Oct. 29, 1946 2,463,926 Ward Mar. 8, 1949 

